Case Study Of A Rapid Response Underwater Search For A Tow Missile

In Mid July 2006 the USAESCH began searching for a prototype TOW missile using underwater EM61 and magnetometer sensors. The missile was lost in Indian Creek, on Redstone Arsenal in Alabama, and its flight motor was needed to analyze telemetry data. More than three weeks of searching with analog detectors proved fruitless. Believing digital mapping techniques would be easy, we quickly learned that variable current, confined operating areas and bottom obstructions will wreak havoc on the best of plans. Even anomaly marking and recovery proved a challenge in current and zero visibility. Urgency required rapid prototyping of a submersible housing for the EM61 sensor and our initial design placed the coil 0.3m below the water surface while allowing survey speeds of up to three knots. Four conventional missiles and assorted debris were detected using this configuration in shallow waters. In deeper areas we ballasted the housing for bottom-towing but repeated entanglement in sunken trees necessitated a new approach. A dual-sensor magnetometer array was towed at a constant depth of one meter in waters up to 3.5 meters deep and anomalies as small as one-gallon welding rod containers were found. The prototype missile was recovered in early August.